1. Field of the invention
The present invention relates to a brake liquid pressure control unit of an on-vehicle device including a control mechanism in a brake system such as an anti-lock brake system (ABS), a vehicular motion control system, a traction control system and its manufacturing method.
2. Description of the Related Art
Such a kind of brake liquid pressure control unit as described above is exemplified by an international patent application publication official gazette No. WO99/25594 published on May 27, 1999.
The previously proposed brake liquid pressure control unit as disclosed in the above-described publication, a liquid pressure circuit including a liquid pressure device such as a pump is disposed on a base block in substantially a rectangular parallelepiped formed of an aluminum material. A pump driving motor and an electronic circuit board block to control an electromagnetic valve or another electronic device are attached onto two surfaces, i.e., a first base surface and a second base surface which faces against each other in mutually opposing direction.
In addition, a reservoir in which a piston and bias device are housed is disposed with a space enclosed by a cylindrically shaped hole and a lid member. The reservoir temporarily reserves a working liquid (brake liquid) within the liquid pressure circuit. The cylindrical hole of the reservoir is formed on the second base surface on which the electronic circuit board block is attached and the lid member attached onto an opening end of the cylindrically shaped hole is projected into a covering of the electronic circuit board block.